Masterbatches of single wall carbon nanotubes (SWCNTs), multi-wall carbon nanotubes (MWCNTs), graphene (G), reduced graphene oxide (RGO) and nitrogen doped graphene (NDG) were used at 0.5, 1.0, and 2.0 wt% to produce electrically conductive and piezoresistive nanocomposites. The conductivity and piezoresistive response was dependent on the microstructure obtained. A unified processing route incorporating mechanical mixing and ultrasonication was used. Distance between electrode points affected the final measurements and a minimum measurement distance of 2 cm was identified. Digital image correlation (DIC) was employed to measure strain during tensile loading. For all materials, an increase in the wt.% of nanoparticles resulted in lower resistivity. Resistivities for CNT samples ranged between 2 and 106 Ohm⋅cm as compared to G/RGO/NDG samples, 1011–1012 Ohm⋅cm. Strain based gauge factors for CNT samples ranged up to ~ 7 while to G/RGO/NDG masterbatches were found to be unsuitable for self-diagnostic applications.
- Carbon nanotubes